In many technical appliances which contain a radio-frequency transmitter or receiver and at the same time have a high-voltage with respect to ground (mains voltage) conductively applied to them, an antenna is intended to be connected via a coaxial cable. The corresponding antenna and the coaxial cable must be galvanically isolated from the appliance since there would otherwise be a lethal danger if they were touched.
Until now, the problem has been solved, for example by two dipole antennas arranged parallel in the appliance, although this results in a high continuity attenuation of at least 6 dB for the useful signal, because of the undesired radial emission. The output power was fed into a coaxial cable in order to be passed on to a remote antenna.
Known decoupling using capacitors (U.S. Pat. No. 4,987,391) has either a low dielectric strength (1 kV) or a high continuity attenuation, since capacitors have to be physically large for a high dielectric strength, and this has a negative effect on the attenuation, because of the high inductive reactance and the undesirable emission.
It is known from the document U.S. Pat. No. 7,545,243 that line structures are suitable for galvanic decoupling.
However, one disadvantage of this known solution is likewise the low dielectric strength.